Propulsion unit for an electric pedal-assisted cycle and pedal-assisted cycle thereof

Abstract

Propulsion unit for an electric pedal assisted cycle (EPAC) comprising an electric machine having a stator and a rotor, rotatable about a motor axis, said rotor (16) being operatively connected to a crank pin, defining a crank axis, mechanically connected to the pedals, wherein the propulsion unit comprises at least an electronic unit for operating and controlling the functioning of the electric machine, wherein the propulsion unit comprises at least a pair of housings defining a containment space which houses the electric machine and at least partially the crank pin, wherein the propulsion unit comprises transmission means of the motion from the rotor to the crank pin, wherein the electronic unit is contained and supported inside said containment space by an intermediate support element.

The invention claimed is: 
     
       1. Propulsion unit for an electric pedal-assisted cycle (EPAC) comprising an electric machine having a stator and a rotor, rotatable about a motor axis, said rotor being operatively connected to a crank pin, defining a crank axis mechanically connected to pedals,
 wherein the propulsion unit comprises at least one electronic unit for operating and controlling the functioning of the electric machine, 
 wherein the propulsion unit comprises at least a pair of housings defining a containment space which houses the electric machine and at least partially the crank pin, 
 wherein the propulsion unit comprises transmission means of the movement from the rotor to the crank pin, 
 wherein the electronic unit is contained and is supported inside said containment space by an intermediate support element, wherein said intermediate support element also supports said rotor and the intermediate support element is contained in the containment space, said intermediate support element being in contact with at least one of said housings so as to dissipate heat through the pair of housings to the outside of the propulsion unit. 
 
     
     
       2. Propulsion unit according to  claim 1 , wherein the propulsion unit comprises at least one cylindrical element which mechanically connects said intermediate support element to the electronic unit, said cylindrical element being a thermal conductor configured to extract the heat from the electronic unit to the intermediate support element and from the latter to the outside of the housings. 
     
     
       3. Propulsion unit according to  claim 2 , wherein at least one of said cylindrical elements is provided with an oval cross-section with respect to a cross-section plane perpendicular to a main extension axis of said cylindrical element. 
     
     
       4. Propulsion unit according to  claim 1 , wherein the electronic unit is provided with at least one electric cable and at least one corresponding conduit, the conduit being attached to the electronic unit by at least one means of attachment, the conduit and/or attachment means being thermal conductors in order to dissipate the heat from said electronic unit. 
     
     
       5. Propulsion unit according to  claim 1 , wherein the rotor and the electronic unit are positioned on axially opposite sides in relation to said intermediate support element, along the crank axis. 
     
     
       6. Propulsion unit according to  claim 1 , wherein the intermediate support element is arranged around the crank axis and fixed in relation thereto. 
     
     
       7. Propulsion unit according to  claim 1 , wherein said crank axis is coaxial with the motor axis. 
     
     
       8. Propulsion unit according to  claim 1 , wherein said transmission means are arranged in an asymmetrical position overall and decentralised from the crank axis, so as to be outside the projection of the rotor on a projection plane perpendicular to the crank axis. 
     
     
       9. Propulsion unit according to  claim 1 , wherein the rotor is coaxial and external to the stator so as to radially enclose the stator. 
     
     
       10. Propulsion unit according to  claim 1 , wherein the electronic unit is positioned so as to fall inside the projection of the rotor on a projection plane perpendicular to the crank axis. 
     
     
       11. Propulsion unit according to  claim 1 , wherein the electronic unit is positioned on the opposite side to a drive means overall, in relation to the crank axis. 
     
     
       12. Propulsion unit according to  claim 1 , wherein the electronic unit is generally shaped as a ‘C’ around the crank axis. 
     
     
       13. Bicycle comprising a propulsion unit according to  claim 1 , wherein, a direction of advancement of the bicycle having been defined, the propulsion unit is associated and oriented in relation to a bicycle frame so that the electronic unit is positioned at least partially on the side of the direction of advancement.